What does a negative Urine Drug Screen (UDS) result mean for a patient taking Ativan (lorazepam)?

Interpreting a Negative Urine Drug Screen in a Patient Taking Ativan

A negative urine drug screen (UDS) in a patient taking Ativan (lorazepam) most likely indicates that standard immunoassay testing does not detect this specific benzodiazepine, rather than non-compliance or diversion.

Why Lorazepam May Not Show Up on Standard UDS

Standard benzodiazepine immunoassays have significant limitations in detecting certain benzodiazepines:

• Most benzodiazepine panels are designed to detect oxazepam (a common metabolite of many benzodiazepines) 1
• Lorazepam (Ativan) does not metabolize through the oxazepam pathway and is therefore commonly missed by standard screening tests 1, 2
• This creates a "clinical false-negative" result - the patient is taking the medication as prescribed, but the test fails to detect it 1

Interpreting Negative Results

When faced with a negative UDS in a patient prescribed Ativan:

1. Do not assume non-compliance or diversion

   • A negative test does not exclude the possibility of drug use or indicate that the patient is not taking their medication 1
   • Avoid making accusations that could damage the patient-provider relationship

2. Consider test limitations

   • Standard immunoassay panels have known detection gaps 1, 2
   • The detection window may have been missed (most drugs are detectable for only 72 hours) 1

3. Evaluate for other explanations

   • Dilute urine specimen (check urine creatinine if available) 1
   • Laboratory error or improper specimen collection 1
   • Medication interactions affecting metabolism 2

Next Steps

If confirmation is clinically necessary:

1. Order specific confirmatory testing

   • Request gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-mass spectrometry (LC-MS) specifically for lorazepam 1, 3
   • These more specific methods can reliably detect lorazepam when standard screens cannot 2

2. Improve future testing accuracy

   • Ensure the laboratory knows which medications the patient is taking 2
   • Request a comprehensive benzodiazepine panel that includes lorazepam specifically 3
   • Consider first-morning specimens which generally provide more concentrated samples 1

Common Pitfalls to Avoid

• Dismissing patients based on UDS results alone

  • This could constitute patient abandonment and adversely affect patient safety 1
  • It may result in missed opportunities to provide potentially lifesaving interventions 1

• Overinterpreting negative results

  • A single negative test does not exclude substance use or confirm diversion 1
  • False-negative results might inadvertently delay detection of substance use disorders if symptoms are dismissed 1

• Failing to discuss results with patients

  • Discussing unexpected results with patients can often yield explanations that obviate the need for expensive confirmatory testing 1

Remember that UDS is just one tool in patient assessment and should be interpreted within the clinical context, with an understanding of the specific test's limitations.